When college classmates learn he was a machine gunner for the Marine Corps for two tours in Iraq, they want to know: Did anyone ever shoot at you? Ever get hit?

And there's the big one.

You ever kill anyone?

"It's unusual, I understand that, what I've done," says Bathgate, 24, of Dundalk, now out of the military and studying kinesiology at Towson University. "Still, it's annoying. … Naturally, I feel different" from the other, mostly younger students on campus.

It's a feeling shared by many. More than a decade of war has minted a new generation of veterans: Two and a half million Americans have served in Iraq or Afghanistan since Sept. 11, 2001.

The challenges now confronting some of them are well-documented: limbs lost, post-traumatic stress disorder and traumatic brain injury; an unemployment rate greater than the national average; an alarming incidence of suicide.

But others describe a more subtle challenge: the difficulty of returning to civilian life in a society that generally appreciates their service — but doesn't always understand it.

While most of the nation's young men served during World War II, and the United States maintained a draft that drew broadly from the country for the conflicts in Korea and Vietnam, military service now is increasingly the province of a shrinking minority of Americans. The number who have been to war in the last decade amounts to less than 1 percent of the U.S. population.

"It's isolating," says Patrick Young, the coordinator of veterans services at Towson. "There's a disconnect between people serving in the military and the civilian populace that benefits from their service.

"It's not necessarily a bad thing," says Young, 29, a former Marine who deployed twice to Iraq. "It's just the reality. … Where in World War II you had a majority of people who had gone through some of the same experiences, or at least was forced to put their lives on hold for an effort that everybody thought was righteous, now you come back, and [some people] who haven't served assume you're crazy or think you have some sort of mental disorder."

"They thank you for your service," says Tarlton, 24, a former Marine artillery scout observer who served two tours in Afghanistan. "They're very polite. But then every once in a while you get the nut case who calls you a baby-killer.

"I would say it's rare, honestly. Now, I have met some veterans who say they get that more than the compliments. And I have no idea where they could possibly live at where that happens. But I would like to pay them a visit."

More common, veterans say, are the moments when cultures clash — when the blunt talk or the black humor that are common in the military horrify a listener who never served.

"You're used to talking one language in the military," says Howard Denney, 36, who remains a Marine reservist after two deployments to Iraq. "Then you try to go back into the civilian world, where a simple joke that you think everybody would get, the civilians don't get."

"People know you've been in the military because of the way you handle yourself," Young says. "They say, 'I could tell, because of how direct you are.'"

The reactions of civilians aren't the only challenges that await returning veterans. Several speak of the difficulty adjusting to the freedom of civilian life, after the discipline and structure of the military.

For the first three months after Young left the Marines, he says, "I was just drinking my face off and watching TV."

"You just didn't have a mission anymore," he says. When you're still in uniform, he says, "you think about getting out and getting away from this micromanaging system that takes away from your freedom. But when you finally have that freedom back, it's overwhelming.

"That's the nature of growing up, I think. It's just that for military people, you have that system of people telling you what you need to do, telling you where you're supposed to be. And then when it's thrown back to you, you're kind of like, 'What do I do now?'"

Young eventually figured it out. He graduated from Towson with a triple major in political science, religious studies and philosophy, with a minor in theater. He now works full-time on campus as the veterans services coordinator.

Erin Byers found a way to settle back into civilian life. After leaving the Army last year, the Frederick woman landed a fellowship with The Mission Continues, an organization that directs veterans in community service projects.

She recently completed her fellowship working with the Veteran Artist Program, a Baltimore-based organization that supports veterans in their artistic pursuits and productions.

"That was a really, really awesome tool for my transition," said Byers, 36, a former combat medic whose seven years in uniform included a tour in Iraq. "I was able to still utilize my military training, my leadership abilities, my training leading other people in certain tasks in somewhat of a military fashion, yet applying it to the civilian world.

"It also gave me other veterans to network with, so I know all these other veterans that are like-minded, wanting to still give back to their communities, and do service projects. So I still have close-knit veteran friends. As opposed to some people, they just get out of the military, they have no real connection to a group of people."

It's to help veterans avoid isolation that Towson, UMBC and other schools have opened centers for their students who have served. The Veterans Center at Towson, which opened two years ago, helps connect veterans with their GI Bill benefits, with programs on campus, and with each other.

The last is particularly helpful for students who tend to be older than their classmates and have lived through experiences that other students can't understand.

"Everyone feels like children," says Joshua Bortell, 28, a former Marine from Essex now studying computer science at Towson. "Some of it might be the age difference, but I don't think all of it. Everyone feels less mature.

"That's not necessarily a bad thing. They're just out of high school."

On a recent afternoon, the Veterans Center, on the ground floor of Towson's Psychology Building, saw a steady stream of young men and women who came to use the computers, talk over coffee or catch up with some sleep on one of the soft purple couches.

"In the very first weeks of class, there's always the same conversations," Young says. "It's, 'You won't believe what this kid said, what that kid's complaining about.' But before we had this here, you'd just be brooding to yourself about it.

"Now it's this kind of non-intended decompression where they realize they're all going through it, and they're not crazy. They're not the only ones who are suffering or being pissed off by some of the things that their now-younger peers are going through."

After 20 years in the Army, Michelle Adamski is delighted to be on a college campus. In Afghanistan, she ran mortuary collection points, where soldiers gathered remains to send back to the United States for burial.

Now the 44-year-old Freeland woman, a onetime drill sergeant, is studying early education. She wants to teach.

"What I was doing before, it's anti-life. It's depressing," she says. "And here, there's so much vibrancy, and so much life — it's nice, it's very nice."

Bathgate, the former Marine Corps machine gunner, says the discipline he learned in the service is serving him in school.

"Instead of just giving up and saying I'll just drop the class or withdraw, no matter how stressed-out or no matter how overwhelmed I get, the determination just to keep studying, to keep going, that doesn't stop."

Having survived two deployments to Iraq, he says, "almost makes me feel invincible."